Tanix TX3 comes in at least two versions, the QZ mentioned just above, and a BZ version. The name on the PCB is the only way to figure out.
Maybe because I pre-ordered the box, I unfortunately got an even earlier version, my PCB says CS_905X3_TX95_B4_V1.1. This variant has 100M eth.
On this box I followed Hannah's first post and got all working but the eth - no surprise
The excerpt from boot log is the following:
[ 3.523773] meson8b-dwmac ff3f0000.ethernet: IRQ eth_wake_irq not found
[ 3.528711] meson8b-dwmac ff3f0000.ethernet: IRQ eth_lpi not found
[ 3.534944] meson8b-dwmac ff3f0000.ethernet: PTP uses main clock
[ 3.540791] meson8b-dwmac ff3f0000.ethernet: no reset control found
[ 3.548747] meson8b-dwmac ff3f0000.ethernet: User ID: 0x11, Synopsys ID: 0x37
[ 3.554075] meson8b-dwmac ff3f0000.ethernet: DWMAC1000
[ 3.559232] meson8b-dwmac ff3f0000.ethernet: DMA HW capability register supported
[ 3.566646] meson8b-dwmac ff3f0000.ethernet: RX Checksum Offload Engine supported
[ 3.574061] meson8b-dwmac ff3f0000.ethernet: COE Type 2
[ 3.579238] meson8b-dwmac ff3f0000.ethernet: TX Checksum insertion supported
[ 3.586223] meson8b-dwmac ff3f0000.ethernet: Wake-Up On Lan supported
[ 3.592664] meson8b-dwmac ff3f0000.ethernet: Normal descriptors
[ 3.598473] meson8b-dwmac ff3f0000.ethernet: Ring mode enabled
[ 3.604250] meson8b-dwmac ff3f0000.ethernet: Enable RX Mitigation via HW Watchdog Timer
[ 13.829376] meson8b-dwmac ff3f0000.ethernet eth0: PHY [0.1:08] driver [Meson G12A Internal PHY] (irq=34)
[ 13.840836] meson8b-dwmac ff3f0000.ethernet eth0: No Safety Features support found
[ 13.840849] meson8b-dwmac ff3f0000.ethernet eth0: PTP not supported by HW
[ 13.840859] meson8b-dwmac ff3f0000.ethernet eth0: configuring for phy/rmii link mode
As I have built-in WiFi working (very poorly implemented) and also an external WiFi USB interface working great, eth is a low priority, yet it would be nice to figure it out.